This must be one of the most important things you can teach a parrot to do, but many parrots - and this includes all parrot-like birds right down to budgies, cockatiels, parrotlets and lovebirds - are not trained to do this.
In the October issue Michael Simmons, one of the top parrot trainers in the country, explains how parrot owners should go about this, and says all parrots, whatever their background, have the ability to learn this task!